Longitudinal hole forming method for layered thermal barrier coating based on reverse deformation, and thermal barrier coating

Abstract

The invention discloses a longitudinal hole forming method for a layered thermal barrier coating based on reverse deformation, and the thermal barrier coating. The layered thermal barrier coating withlow thermal conductivity is prepared by adopting a conventional plasma spraying process; and then transverse tensile stress is formed in the coating through a reverse deformation method, large-scalelongitudinal pores are formed in the layered thermal barrier coating in the heat flow direction, the pore depth is 20%-100% of the thickness of the coating, and the pore interval is 0.5-10 times the thickness of the coating. In a high-temperature service environment, the layered structure with the low thermal conductivity can effectively block a heat flow, so that a high heat insulation effect isachieved; the overall rigidity degree of the coating in high-temperature service can be remarkably decreased through large-scale longitudinal pores, and therefore the effect of greatly prolonging theservice life of the coating is achieved through the low-cracking design; and the purpose of forming the large-scale longitudinal pores in the high-thermal-insulation layered thermal barrier coating ata low temperature is achieved, and the collaborative optimization effect of high thermal insulation and long service life is expected to be achieved.

Description

technical field [0001] The invention relates to the technical field of coatings, in particular to a preparation method of a thermal barrier coating and the thermal barrier coating. Background technique [0002] Thermal barrier coatings are widely used in aero-engines and ground gas turbines. The main function is to reduce the load-bearing temperature of metal-based hot-end components and prevent them from failing in environments higher than their own temperature-bearing limits. For example, at present, the turbine inlet temperature of the H-class heavy-duty gas turbine has reached 1600 °C, and the temperature bearing capacity of the hot end parts is required to reach more than 1400 °C. However, the temperature limit of current state-of-the-art single crystal superalloys is only about 1100°C. Therefore, corresponding cooling protection measures must be taken to ensure the stable operation of the hot end components. Thermal barrier coating is one of the necessary thermal ins...

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Problems solved by technology

Existing methods mainly focus on two aspects: (1) Obtain a relatively dense structure, densify the structure, obtain a large pore-forming stress by increasing the apparent elastic modulus, and then form pores longitudinally; however, the relatively dense structure It inevitably sacrifices the thermal insulation ability of the coating in the longitudinal direction; (2) Increase the pretreatment temperature of the coating (mostly 800°C to 1400°C) to obtain a larger shrinkage deformation, thereby increasing the pore-forming stress, but the higher temperature It often inevitably causes the sintering and densification of the coating, and also has a certain weakening effect on the heat insulation of the coating.

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